In a principal aspect, the present invention relates to a tool which can be used to extract a bolt or screw from a bore where the head of the bolt or screw has been removed, for example, by fracture or otherwise. The tool is typically termed a bolt and screw extractor and is part of a family of tools having the form of a tap.
Heretofore, such tools have been available and typically include a hexagonal head which can be turned by a wrench or the like and an extractor or broach end which is driven into a counterbore drilled into the bolt or screw. The extractor end or broach end is typically fluted, for example, by knurling so that V-shaped grooves and ribs extend longitudinally around the periphery of the broach end of the tool. In this manner, when the tool is driven into a hole drilled in a bolt or screw, the ribs will grip or cut into the sides of the hole. The tap or extractor may then be rotated, for example, by a wrench to thereby extract or remove the bolt or screw.
Heretofore, the steel commonly used to make such extractors has the ANSI designation as S7 steel. More recently, a new steel material has been utilized for such extractor tools; namely, ANSI S2 designation steel. The new steel has been useful, but has some inherent problems because it is notch sensitive. That is, the V-shaped slots cut in the side of the tool to form the ribs, will fracture when subjected to stress, thus destroying the capability of the tool to serve as an efficient extractor. The present invention addresses this, among other problems.